valve cover baffles question>?

Ok, so my pcv port busted the other night. Didnt realize the opening was about 1/8 '' and grinded it down and I am going to put a 90 degree 5/16 fitting there. I was going to drill it down and tap it, but there is a tube sitting in the opening and was wondering if anyone knows if the tube/sleeve goes all the way down the baffle (atleast to the opening) and how much room do I have to drill down to tap into it?

I just want to know if it will be easier to grind off the rivets and pull the inside cover off or can I just drill into the tube. Or will it fall or break off? Do I need the tube? or can ditch the small tube?

Mike